Effect of Nanofiller Calcination on Breakdown Performance of Zirconia Based Polyethylene Nanocomposites

Dielectrics are widely used in electrical and high voltage systems. Studies on new dielectric materials, especially polymer nanocomposites, have been extensively carried out in order to investigate the potential improvements of the materials in high voltage insulation. Significantly, the interface between the base material (polymer) and the nanofiller is a vital factor that influences the dielectric performance of the materials. This paper reports on an investigation into the AC and DC breakdown performance of unfilled and polyethylene nanocomposites containing zirconium oxide (ZrO2) nanofillers at different amounts; 1 wt%, 4 wt%, and 8wt%. The chemical structures of the materials were characterized using Fourier transform infrared (FTIR) spectroscopy. Dielectric spectroscopy was used to measure the dielectric permittivity of the samples. Breakdown testing showed that there were no significant changes on the AC breakdown behaviors of nanocomposites containing both uncalcined and calcined nanofillers. Meanwhile, substantial changes were observed on the materials' DC breakdown strength, even by introducing a small amount of nanofiller (1 wt%); the DC breakdown strength of the nanocomposites enhanced for those containing calcined nanofillers compared to uncalcined nanofillers. The observation is associated with the calcination process of the nanofillers.